1. Field of the Invention
This invention relates to an applicator for cosmetics which is adapted for use in the application of cosmetics or skin lotions to human skin surfaces.
The term “an applicator for cosmetics” used herein is intended to mean those instruments which are used for applying cosmetics or skin lotions to human skin surfaces, and include sponge puffs for cosmetics, eye shadow chips, putting sponges, applicators for rouge, applicators or brushes for cheek rouge and the like.
2. Description of the Related Art
At present, foamed rubber materials that are ordinarily used for this type of applicator, particularly, a sponge puff for cosmetic purposes, include acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene terpolymers (EPDM), urethane rubbers, silicone rubbers and the like.
For the method of obtaining a foamed rubber material of a high degree of foaming or expansion used for sponge puffs for cosmetics, there are known a number of methods including a method wherein a blend of a rubber, a blowing agent, a crosslinking agent and the like is packed in a mold, heated under pressure, followed by depressurization to obtain a foamed material, a method wherein a crosslinking agent is added to a rubber latex, followed by mechanically agitating the mixture for foaming, pouring the mixture into a mold and heating, and the like. However, all of these methods are disadvantageous in that because they are a batch process, their productivity is poor.
For a sponge puff, there is known a latex foam puff, which is obtained by mechanically foaming and vulcanizing a rubber latex composition. This puff has the problem that a limitation is placed on an open-cell foam and a great number of cylindrical molds similar to a product shape are required.
Some closed-cell sponge puffs are also known, which are made of expanded materials obtained by adding a blowing agent and the like additives to a solid rubber, packing the mixture in a mold, and heating under pressure to obtain a sponge material. The rubber sheet removed from the mold should be punched out in a form similar to an intended shape of the product, with the attendant problems of a great loss of the material and poor productivity resulting from its batch process.
Further, urethane sponge puffs are known in the art, wherein a solvent-containing urethane resin composition is extruded, and the solvent is evaporated off under a reduced pressure to form cells therein. This process also has the problems that the material loss is great and a load on recovery of the solvent is serious.
Composite puff articles of latex foam puffs, closed-cell sponge puffs, urethane sponge puffs and puffs made of other types of materials are also known, with the problems that molding of a multi-layered structure is difficult, coupled with an increasing number of additional steps including post-treatment.
A foundation, which is a kind of cosmetic, is classified into a powder-type and a liquid-type. The powder foundation is one wherein pigments and the like are solidified with a paraffin oil or the like, and the liquid foundation is a liquid one wherein solid matters such as pigments are dispersed in water or a silicone oil.
In general, the sponge puff used for the powder foundation is made of an open-cell foam of NBR (nitrile rubber) or a urethane rubber. Especially, an NBR open-cell foam is one which is obtained by mechanically mixing air into a latex and foaming the mixture and whose foamed conditions are uniform throughout the resulting foam with a water absorption being at 500% or over. When this open-cell sponge puff is applied for a liquid-type foundation, the foundation infiltrates into the puff, which makes it difficult to permit the liquid foundation to be deposited on the skin. Thus, such an open-cell sponge puff is unsuitable for a liquid foundation.
Sponge puffs adapted for use in liquid foundations include those sponge puffs made of closed cells such as of silicone rubbers and EPDM (ethylene/propylene rubbers), sponge puffs wherein a skin film is applied onto open-cell sponges, and the like. The closed-cell sponge puffs are those which are expanded under heat and pressurizing conditions with the use of a press and are made of fine foams having a size of 100 μm or below and which cannot be manufactured in a sheet thickness of 30 mm or over because of the application of heat from a hot press. Although the water absorption is less than 5%, this type of puff is not good, with respect to a feel to the touch, owing to the elastic feeling inherent to the closed cells. When this type of puff is applied for powder foundation, it is unlikely to cause a powder foundation to be appropriately deposited thereon due to the fineness of the cells and such a puff runs as sliding on the skin surface, thus being not suited for application to powder foundations in practice.
Those sponge puffs used for liquid-type foundation, in which a skin film is attached to open-cell sponges, are made by attaching a skin film to a latex foam, so that the cells partly collapse. The liquid infiltrates in use from the skin film-free side surface. This presents the problems that hands are soiled, the liquid remains inside, thus lacking in sanitation, and the skin film portion becomes stiff and slippery.